Fabrication of poly(N-isopropylacrylamide) nanoparticles using a simple spray-coating method and applications for a QCM-based HCl gas sensor coating

We propose a new simplified fabrication process for poly(N-isopropylacrylamide) (PNIPAM) nanoparticles for a quartz crystal microbalance (QCM)-based HCl gas sensor coating. PNIPAM solution, synthesized via atom transfer radical polymerization (ATRP) below a lower critical solution temperature (LCST), is simply sprayed onto a heated quartz resonator surface at 50 degrees C; nanoparticles with a mean diameter of 100 nm were successfully formed with this method. The PNIPAM nanoparticles produced exhibited a large HCl gas sensor response, and the magnitude of the response increased linearly with PNIPAM loading on the resonator. However, the value of the recovery was unexpectedly less than 90%. The hydrogen-bonding structure of the nanoparticles produced was characterized by water vapor adsorption measurement and FTIR analysis in a humid atmosphere. (C) 2017 Elsevier B.V. All rights reserved.